An ADU needs a permitted drawing set before anything is built: a site plan, floor plans, elevations, sections and the structural, electrical, plumbing and energy information the city needs to review. Yeganeh Inc. prices plans and permitting separately from construction, from $5,000 to $7,000 for an attached garage conversion up to $12,000 to $16,000 for a two-story ADU. Review typically takes around two to three months, depending on the city and the project.
Written for homeowners deciding whether to start with drawings, and for those who have been quoted a design fee and want to know what it buys.
What an ADU plan set actually contains
"Plans" sounds like one drawing. It is a set, and the size of the set is why design is a real line on the budget rather than a formality.
At minimum it establishes where the unit sits on the lot relative to boundaries and existing structures, what the internal layout is, what the building looks like from each side, how it is put together, and how the structure, electrical, plumbing and energy performance satisfy code. Cities review all of that, and they review it against the version of the rules current when you submit.
The drawings serve two audiences with different needs. Plan check needs to see compliance. The people building it need to see how it goes together. A set that satisfies the first and not the second is where the awkward conversations in month two come from.
Design and construction, together or separately
You can hire a designer, get drawings, then take those drawings to builders for pricing. Plenty of people do, and it is a legitimate way to run a project.
We handle plans and permitting alongside construction instead, and the argument for it is straightforward: the people who drew it are the people who have to build it, so the set tends to be buildable rather than merely approvable. It also removes the gap where a design decision that adds cost is nobody's problem until it is your problem.
The argument against it is equally straightforward: you are committing earlier. Which is why the ranges are published: so you can see what the design stage costs before you decide how to run it.
What plans and permitting cost
Priced separately from construction on every project, and quoted before design work starts.
- Attached garage conversion: $5,000 to $7,000
- Detached garage conversion: $5,000 to $10,000
- One-story attached or detached ADU: $7,000 to $12,000
- Two-story detached ADU: $12,000 to $16,000
How long plan check takes
Permitting often takes approximately two to three months, depending on the city and the project.
The variable part is corrections. Plan check rarely approves a set outright on the first pass; it comes back with comments, those get addressed, and it goes round again. How many rounds that takes depends on how complete the initial submission was, which is the one part of the process a builder can actually influence.
What nobody can do is guarantee an approval date, and it is worth being wary of anyone who offers to.
Pre-approved and standard plans
Several California jurisdictions now run pre-approved or standard ADU plan programmes, where a set of designs has already been reviewed and can move through permitting faster.
Whether one is available for your property, and whether it suits your lot, depends on your jurisdiction and on the site. We check what applies to your address as part of the property visit rather than making a general claim about it here. Programmes of this kind change, and a page that states their content confidently is a page that will be wrong within a year.
Designing for the lot rather than the catalogue
The decisions that matter most in an ADU design are usually not aesthetic. Where the unit sits relative to setbacks and the existing house. Where its front door faces, and whether anyone has to walk past a bedroom window to reach it. Where the utilities come from. Whether the outdoor space that is left over is usable or merely leftover.
Get those right and a small unit feels generous. Get them wrong and no amount of specification rescues it.
Junior ADUs (JADUs) in Los Angeles
